Effect of Particle-Substrate Interactions on Colloidal Layer Structure Prepared by Convective Self-Assembly Using Polyelectrolyte-Grafted Silica Particles.

Cationic and anionic polyelectrolytes, poly(vinylbenzyl trimethylammonium chloride) (PVBTA) and poly(sodium styrene sulfate) (PSSS), were grafted on the surface of the silica particles, respectively, and then these two types of polyelectrolyte-grafted silica particles were applied to the colloidal layer preparation by convective self-assembly (CSA) using hydrophilic or hydrophobic glass substrates to investigate the effect of the interactions between the particles and the substrate surface on the resultant layer structures. When the PVBTA-grafted silica particle (PVBTA-Si) was used, the colloidal monolayers with a non-close-packed (NCP) structure were formed on both hydrophilic and hydrophobic glass substrates, where the NCP colloidal layers on the hydrophobic glass substrate have a somewhat more ordered structure than those on the hydrophilic glass substrate. In the case of the PSSS-grafted silica particle (PSSS-Si), on the other hand, stripe patterns with close-packed (CP) colloidal layers were obtained on both types of the glass substrates. The number of layers of the stripes on the hydrophilic glass substrate was less than that on the hydrophobic glass substrate, while the spacing and width of the stripes on both substrates were similar to each other. The difference in the structures of the colloidal layers obtained here indicates that an attractive interaction, such as an electrostatic attraction and a hydrophobic interaction, between the particle and the substrate surface is necessary to achieve the NCP structure by the CSA process using polyelectrolyte-grafted silica particles.

Multilayered Gel-Spotting Device for In Vitro Reconstruction of Hair Follicle-like Microstructure.

Hair follicles play an important role in hair development. This study aimed to develop a microgel-spotting device to fabricate a multilayered gel bead culture model and to mimic the early development of skin appendages to regenerate hair follicles in vitro. The model consists of an alginate gel layer containing cytokines as the core layer, a collagen gel layer containing mouse embryonic stem cells as the middle layer, and a collagen gel layer containing fetus-derived epidermal cells as the outer layer. A concentration gradient of cytokines is formed, which promotes interactions between epidermal and stem cells. Histological and immunnohistological analyses confirmed the reconstruction of hair follicle structures. As a result, the cell number and gel bead size could be precisely controlled by the developed microgel-spotting device. In the multilayered gel bead, the embryonic and epidermal cells cultured with the cytokine gradient formed cell aggregates with keratinized tissue in the center similar to "native" hair follicle structure. Sweat gland-like luminal tissue and erector pilorum-like structures were also observed around aggregates with concentric structures. In conclusion, the multilayered gel bead culture model demonstrated potential for in vitro hair follicle regeneration. The findings of this study provide insight into the early development of skin appendages.

Anthropogenic Pu distribution in Tropical East Pacific.

The geographical distribution of the anthropogenic radionuclides (238)Pu and (239+240)Pu in the Tropical East Pacific in 2003 was studied from the viewpoint of material migration. We measured the contents of Pu isotopes in seawater and in sediment from the sea bottom. The distributions of Pu isotopes, together with those of coexisting nitrate and phosphate species and dissolved oxygen, are discussed in relation to the potential temperature and potential density (sigma-θ). The Pu contents in sediment samples were compared with those in the seawater. Horizontal migration across the Equator from north to south was investigated at depths down to ~800m in the eastern Pacific. The Pu distribution at 0-400m correlated well with the distribution of potential temperature. Maximum Pu levels were observed in the subsurface layer at 600-800m, corresponding to the depth where sigma-θ≈27.0. It is suggested that the Pu distribution depends on the structure of the water mass and the particular temperature and salinity. The water column/sediment column inventory ratio and the vertical distribution of Pu may reflect the efficiency of scavenging in the relevant water areas.

Thrombin generation by intimal tissue factor contributes to thrombus formation on macrophage-rich neointima but not normal intima of hyperlipidemic rabbits.

Arterial thrombosis occurs in atherosclerotic, but rarely in non-atherosclerotic arteries. The present study investigates how hyperlipidemic condition affects thrombus formation on macrophage-rich neointima or normal intima in rabbits. Rabbits were fed with a 0.5% cholesterol diet, and then the femoral artery on one side of each rabbit was injured with a balloon catheter. Three weeks later, bilateral femoral arteries were similarly injured with a balloon catheter to produce thrombi on neointima and normal intima. We compared the expression and activity of intimal tissue factor (TF) as well as thrombus size and composition between these femoral arteries. 0.5% cholesterol diet combined with a balloon injury induced macrophage-rich neointima in injured arteries. The whole blood coagulation activity or plasma thrombin generation activity did not differ after consuming the 0.5% cholesterol diet for 4 weeks, and an anti-TF antibody did not affect the measured parameters. TF activities were increased in the neointima/media compared with normal intima/media. Balloon injury induced large platelet-fibrin thrombi on macrophage-rich neointima, whereas small platelet thrombi were produced in normal arteries even under hyperlipidemic conditions. Recombinant human tissue factor pathway inhibitor (25microg/(kgmin)) and argatroban (100microg/(kgmin)), a specific thrombin inhibitor, significantly reduced thrombus formation on induced neointima, but not on normal intima. Thrombin generation mediated by TF in intima contributes to thrombus formation on macrophage-rich neointima, but not on normal intima. The TF content in disrupted atherosclerotic plaques might play a more important role than hyperlipidemia in the development of atherothrombosis.

Combined use of brain natriuretic peptide and C-reactive protein for predicting cardiovascular risk in outpatients with type 2 diabetes mellitus.

Appropriate tools are necessary for predicting cardiovascular events in patients with diabetes mellitus because of their high incidence. In this study, we assessed whether a combination of brain natriuretic peptide (BNP) and C-reactive protein (CRP) measurement were useful prognosticators in patients with type 2 diabetes mellitus. One hundred and nine patients with type 2 diabetes mellitus, aged 52 to 93 years, were examined at outpatient clinics for blood, urinary samples, and echocardiography. They were then followed prospectively. During the average follow-up period of 30 months (range, 3 to 37), 15 patients (14%) had cardiovascular events: This was the first event in 5 patients and a recurrence in 10. Cox regression analysis showed that the past event (hazard ratio [HR] 4.819 [95% confidence interval (CI): 1.299-17.881]; p = 0.019) and plasma BNP level (HR 1.007 [95% CI: 1.002-1.012]; p = 0.010] were independently significant factors for the cardiovascular events during the follow-up period. Patients with plasma BNP > or =53 pg/mL and CRP > or =0.95 mg/dL demonstrated the highest incidence in cardiovascular event, compared to those categorized into either or both low levels of BNP and CRP. This study suggests that combination of plasma BNP and CRP measurement provides the additive prognostic information of cardiovascular events in patients with type 2 diabetes mellitus.

Adiponectin produced in coronary circulation regulates coronary flow reserve in nondiabetic patients with angiographically normal coronary arteries.

BACKGROUND: Epicardial adipose tissue expresses adiponectin protein, and its expression is significantly lower in patients with severe coronary artery disease (CAD) than in those without CAD. Transcoronary adiponectin levels are significantly decreased in nondiabetic but not in diabetic patients with CAD. Adiponectin is also an important adipocytokine that is linked to insulin resistance and reduces coronary microvascular function. HYPOTHESIS: Adiponectin may play a significant role in the localized coronary circulation. The present study examines the local dynamics of adiponectin in the coronary circulation in nondiabetic individuals with normal coronary arteries and the relationship between adiponectin and coronary microvasculature function. METHODS: We examined 22 consecutive nondiabetic patients whose coronary arteries were angiographically normal. Plasma levels of adiponectin were measured in blood samples that were simultaneously collected from the orifice of the left coronary artery (LCA) and the great cardiac vein (GCV). To evaluate the function of the coronary microcirculation, we measured coronary flow velocity at maximal hyperemia using a Doppler wire. Coronary flow reserve (CFR) was obtained from the ratio of hyperemia to the baseline coronary flow velocity. RESULTS: Plasma adiponectin levels in the GCV (median 6.95 microg/ml) were significantly higher than those in the LCA (median 6.60 microg/ml, p < 0.0005). The difference in plasma adiponectin levels between GCV and LCA significantly correlated with CFR (R = 0.451, p < 0.05). CONCLUSIONS: Adiponectin is locally produced in the coronary circulation. This protein may participate in modulating the coronary circulation of nondiabetic patients with angiographically normal coronary arteries.

Detection of von Willebrand factor and tissue factor in platelets-fibrin rich coronary thrombi in acute myocardial infarction.

The rapid closure of coronary arteries due to occlusive thrombi is the major cause of acute myocardial infarction. However, the mechanisms of coronary thrombus formation have not been elucidated. We immunohistochemically assessed the localizations and their changes over time of glycoprotein IIb/IIIa, fibrin, von Willebrand factor (vWF), and tissue factor (TF), after the onset of chest pain (<4, 4 to 6, or 6 to 12 hours), in fresh coronary thrombi causing acute myocardial infarction. The occlusive thrombi were consistently composed of platelets, fibrin, vWF, and TF from the early phase of onset, and glycoprotein IIb/IIIa and fibrin were closely associated with vWF and TF, respectively. vWF and/or TF may contribute to occlusive thrombus formation and be novel therapeutic candidates for treating patients with coronary thrombosis.

Effects of interleukin-6 produced in coronary circulation on production of C-reactive protein and coronary microvascular resistance.

We measured plasma levels of interleukin-6 and C-reactive protein at the orifice of the left coronary artery and at the great cardiac vein in patients who had coronary artery disease and those who had angiographically normal coronary arteries (controls). We also measured coronary microvascular resistance in the control group. We found increased levels of interleukin-6 in the coronary circulation of patients who had coronary artery disease compared with controls. This increase correlated with C-reactive protein production in the coronary circulation and coronary microvascular resistance. These findings suggest that a localized cytokine/inflammatory pathway functions in the coronary circulation and that interleukin-6 is involved in modulating coronary vascular tone.